Liquid fuel pumping apparatus

ABSTRACT

A liquid fuel pumping apparatus for supplying fuel to an internal combustion engine includes an injection pump which delivers fuel past a delivery valve. The delivery valve includes an axially movable valve element which is biased by a spring to the closed position, and is movable to the open position by fuel delivered by the injection pump. A restricted passage is provided in the valve element and which allows an additional flow of fuel between the injection pump and an outlet during the delivery stroke of the pump. The flow of fuel through the restricted passage is controlled by a valve member.

Unlted States Patent 1191 1111 3,918,853

Drori 51 Nov. 11, 1975 1 LIQUID FUEL PUMPING APPARATUS 3.465.677 9/1969 Clarke 417/206 3.465.678 9/1969 Mowle 417/206 [76] Inventor: Moshe 6 Camb r1dge Road 3.752.138 8/1973 Gaines 417/462 East Twickenham, Mlddlesex, England Prinmry Examiner-John J. Vrablik [22] Filed; Ma 22, 1974 Altar/1e Agent, or Firm-Kane, Dalsimer, Kane, pp No: 472,435 Sullivan and Kurucz [57] ABSTRACT [30] Foreign Application Priority Data A liquid fuel pumping apparatus for supplying fuel to Ma 25, 1973 United Kingdom 35245/73 an internal combustion engine includes an injection pump which delivers fuel past a delivery valve. The [52] US. Cl. 417/462; 417/558; 137/5651; delivery valve includes an axially movable valve ele- 123/139 BC; 123/139 BD ment which is biased by a spring to the closed posi- [51] Int. CL? F04B 29/00; F04B 21/02; tiOn, and is o able t0 the open position by fuel deliv- F0413 39/10 ered by the injection pump. A restricted passage is [58] Field Of Search 417/458. 462, 558, 206; provided in the valve element and which allows n 123/ 139 AL, 139 BC, 139 B1); ditional flow of fuel between the injection pump and I 137/565}, 565;) an outlet during the delivery stroke of the pump. The

flow of fuel through the restricted passage is con- [56] References Cited trolled by a valve member.

UNITED STATES PATENTS 5 Claims, 1 Drawing Figure 3.363.569 H1968 Roosa 417/206 3.427.979 2/1969 Kemp 417/206 I W I ll l l 2o 21 23 :26 24 27 LIQUID FUEL PUMPING APPARATUS This invention relates to liquid fuel pumping apparatus for supplying fuel to internal combustion engines and of the kind comprising in combination, an injection pump, a distributor member rotatable in a body part,

the injection pump and distributor member being adapted to be driven in timed relationship with an associated engine, the distributor member including a passage communicating with the pumping chamber of the injection pump, and said passage registering in turn during successive delivery strokes of the injection pump with outlet ports formed in the body part and which in use, communicate respectively with the injection nozzles of an assosciated engine, and a delivery valve in said passage, said delivery valve opening during the delivery of fuel by the injection pump.

The object of the invention is to provide such an apparatus in a simple and convenient form.

According to the invention, in an apparatus of the kind specified, said delivery valve comprises an axially v movable valve element, resilient means biasing the valve element to a position in which flow of fuel from said passage to the injection pump is prevented, restricted passage means in said valve element and a valve member in said passage means, said valve member closing to prevent flow of fuel through said passage means from said passage to the injection pump.

One example of a liquid fuel pumping apparatus in accordance with the invention will now be described with reference to the accompanying drawing, which shows a sectional side elevation of a portion of the apparatus.

Referring to the drawing, there is provided a body part in which is mounted a rotary cylindrical distributor member 11. Also provided is an injection pump 12, and the injection pump and distributor member 11 are adapted to be driven in timed relationship with an engine with which the apparatus is associated. In practice, the injection pump comprises a pair of reciprocable pumping plungers which are accomodated within a transversely extending bore formed in the distributor member. Surrounding the distributor member is an annular cam ring on the internal peripheral surface of which is formed a plurality of pairs of inwardly extending cam lobes. Interposed between the internal surface of the cam ring and the plungers are rollers respectively which are mounted upon shoes. As the distributor member rotates, inward movement will be imparted to the plungers, such inward movement occurring during the delivery stroke of the injection pump. The pumping chamber of the injection pump communicates with a passage 13 formed in the distributor member and which communicates with a radially extending passage 14. The radially extending passage breaks out onto the periphery of the distributor member and is positioned to register in turn, and during successive delivery strokes of the injection pump, with a plurality of outlet ports 15 formed in the body part 10. The outlet ports in use are connected respectively to injection nozzles 16 mounted on the associated engine.

The apparatus also includes a feed pump not shown which supplies fuel to the injection pump during the filling strokes thereof, the amount of fuel supplied to the injection pump being controlled by throttling means not shown. The apparatus also includes a delivery valve generally indicated at 17, the delivery valve being positioned in the passage 13.

The delivery valve 17 comprises a valve element 18 slidable within an enlarged portion of the passage 13, and the element 18 is loaded into contact with the step defined in the passage 13 by means of a coiled compression spring 19. Within the vale element 18 is a blind main bore 20 whichthrough ports 21, communicates with a groove 22 formed in the periphery of the valve element. The passage 14 extends from a still further enlargement of the passage 13 and when fuel under pressure is supplied by the injection pump, thevalve element is moved axially until the groove 22 is exposed beyond the step defined between the two enlarged portions of the passage.

Also formed in the valve element and communicating with the closed end of the bore 20 is a restricted passage means which includes a passage 23 defining a restricted orifice opening into a closed chamber 24 from which extend a pair of passages 25. The step defined between the chamber 24 and the passage 23, constitutes a seating for a valve member in the form of a ball 26 and the chamber 24 is closed by a plug 28 which constitutes a stop to limit the movement of the ball. In addition, a main stop 27 is provided to limit the movement of the valve element 18 against the action of the spring 19.

In operation, during an injection stroke of the injection pump, the valve element 18 will be moved by the action of the fuel leaving the injection pump, against the action of the spring 19. The groove 22 will be exposed beyond the aforesaid step to allow flow of fuel from the injection pump to the passage 14. During the supply of fuel by the injection pump, the ball 26 will be lifted from the seating and a proportion of the fuel flowing to the passage 14 will flow by way of the restricted passage means. The quantity of fuel flowing through the passage means depends upon the size of the orifice and the pressure difference across the orifice. The pressure difference will in part be dependendt upon the inertia of the valve element 18. The provision of the passage reduces the rate of movement of the valve element and therefore the rate of compression of the spring and this helps to increase the life of the spring. Moreover, the provision of the ball 26 helps to facilitate the removal of air in the various passages of the apparatus when the apparatus is being primed with fuel.

At the end of the delivery of fuel by the injection pump, the valve element 18 will move under the action of the spring 19. During this process, the ball is maintained in contact with its seating by the pressure of fuel within the passage 14. The volume of fuel therefore relieved from the passage 14 is substantially equal to the displacement of the valve element 18.

I claim:

1. A liquid fuel pumping apparatus for supplying fuel to an internal combustion engine comprising in combination, an injection pump, a body part, a distributor member rotatable in the body part, the injection pump and distributor member being adapted to be driven in time relationship with an associated engine, the distributor member including a passage communicating with the injection pump, the body part having outlet ports formed therein and said passage registering in turn during successive delivery strokes of the injection pump with the outlet ports formed in the body part and which in use, communicate respectively with the injection nozzles of an associated engine, a delivery valve in said passage and containing bore means open in one position to provide communication between said pump and passage and closed by portions of the distributor member in another position, said delivery valve opening during the delivery of fuel by the injection pump, said delivery valve comprising an axially movable valve element, resilient means biasing the valve element to a position in which flow of fuel from said passage to the injection pump is prevented, restricted passage means in said valve element and communicating between the bore means and the passage and a valve member in said passage means, said valve member closing to prevent flow of fuel through said passage means from said passage to the injection pump.

2. An apparatus as claimed in claim 1, in which said valve element is slidable within an enlarged portion of said passage, said passage being provided with a further enlarged portion thereby defining a step between said portions, said valve element having a peripheral groove communicating with the upstream end of the valve element and which during the delivery of fuel by the injection pump is exposed beyond said step as the valve element moves against the action of the resilient means.

3. An apparatus as claimed in claim 2 in which said restricted passage means extends from the upstream end of said valve element and opens into said further enlarged portion of the passage.

4. An apparatus as claimed in claim 3 in which said passage includes a restricted portion constituting a restricted orifice.

5. An apparatus as claimed in claim 4 in which said valve member is in the form of a ball. 

1. A liquid fuel pumping apparatus for supplying fuel to an internal combustion engine comprising in combination, an injection pump, a body part, a distributor member rotatable in the body part, the injection pump and distributor member being adapted to be driven in time relationship with an associated engine, the distributor member including a passage communicating with the injection pump, the body part having outlet ports formed therein and said passage registering in turn during successive delivery strokes of the injection pump with the outlet ports formed in the body part and which in use, communicate respectively with the injection nozzles of an associated engine, a delivery valve in said passage and containing bore means open in one position to provide communication between said pump and passage and closed by portions of the distributor member in another position, said delivery valve opening during the delivery of fuel by the injection pump, said delivery valve comprising an axially movable valve element, resilient means biasing the valve element to a position in which flow of fuel from said passage to the injection pump is prevented, restricted passage means in said valve element and communicating between the bore means and the passage and a valve member in said passage means, said valve member closing to prevent flow of fuel through said passage means from said passage to the injection pump.
 2. An apparatus as claimed in claim 1, in which said valve element is slidable within an enlarged portion of said passage, said passage being provided with a further enlarged portion thereby defining a step between said portions, said valve element having a peripheral groove communicating with the upstream end of the valve element and which during the delivery of fuel by the injection pump is exposed beyond said step as the valve element moves against the action of the resilient means.
 3. An apparatus as claimed in claim 2 in which said restricted passage means extends from the upstream end of said valve element and opens into said further enlarged portion of the passage.
 4. An apparatus as claimed in claim 3 in which said passage includes a restricted portion constituting a restricted orifice.
 5. An apparatus as claimed in claim 4 in which said valve member is in the form of a ball. 